The invention is directed to an apparatus for holding and dispensing metered amounts of at least one active composition into a washing machine, a laundry dryer or a dishwashing machine.
U.S. Pat. No. 4,379,515 discloses a dispensing device for detergent, comprising a rigid container and, communicating with this rigid container by means of a pipe, a compressible reservoir containing the measured quantity of detergent needed for one washing cycle. Under the effect of centrifugal forces generated by rotation of the laundry drum, the reservoir is compressedxe2x80x94particularly if it is disposed between the laundry and the wall of the laundry drumxe2x80x94in such a way that its contents are emptied into the rigid container, where the detergent is then dissolved by the washing liquid. A disadvantage of this dispensing system resides in the fact that the reservoir can be used for only one respective washing cycle and has to be replaced with each new washing cycle.
European patent publication EP 0 215 366 describes a detergent container with a welded seal, wherein the welded seal melts at a specific operating temperature and then releases the detergent. The seal of the container in particular cannot be used again, and in addition it is not possible to dispense more than once with this system.
European patent publication EP 0 328 769 describes a removable dispensing container with a closure that can be opened during a washing cycle and which has a manipulating extension. The pressure exerted by the laundry during the washing cycle causes the manipulating extension to be pushed into the dispensing container in such a way that the detergent is able to flow out. It is not possible to dispense more than one dose and the dispensing container must be filled again before each washing cycle.
German patent publication DE 39 02 356 discloses a dispensing container which may be used for a single washing cycle only and operates on the basis of a temperature-dependent release of a liquid fabric conditioner. The rising temperature causes the pressure in the dispensing container to rise above atmospheric pressure, as a result of which a gate valve is displaced into its open position, permitting the liquid fabric conditioner to flow into the washing machine.
U.S. Pat. No. 5,033,643 describes a dispensing container, which also allows a metering unit to be released for only one washing cycle. Forces generated by the wet laundry act on the release mechanism of the dispensing container.
German patent publications DE 39 34 123 and DE 39 22 342 describe detergent containers which are fixedly mounted on the laundry drum. Pins or locking hooks are used for fixing purposes. With these containers, no provision is made for more than one dose, which means that they have to be removed from the washing machine after every washing cycle and re-filled.
U.S. Pat. No. 5,176,297 describes a dispensing system for a dishwashing machine, which is mounted in the interior of the machine and incorporates a supply and a dispensing compartment. Although it is possible to dispense more than one dose, the dispensing system is controlled by the dishwashing machine in a complex manner.
German patent publication DE 195 40 608 discloses a system enabling more than one dose to be dispensed, in which tablets of dishwashing detergent are placed. The individual doses are controlled by a command issued by the dishwashing machine, i.e., an operating program of the dishwashing machine selected by the user controls the time at which the dose is released.
Australian published patent application AU-A-78393/91 discloses a dispensing container for a detergent, which is dispensed through an orifice opened by the build-up of internal pressure in the container. This internal pressure is generated either by the operating program of the machine or by operation directly on the part of the user.
Summing up the state of the art, dispensing systems are known which primarily permit individual doses to be dispensed and in a few cases multiple doses. In systems permitting a single dose, the release of detergent is generally operated on the basis of a delayed release, which may be triggered by means of a rise in temperature, an increase in pressure or centrifugal forces, for example. What systems permitting multiple doses have in common is that the release is mechanically triggered (valve, piston, gate, etc.) either on the basis of a command issued by the washing program of the machine or by direct operation on the part of the user.
An underlying objective of the invention is to propose an apparatus for holding and dispensing metered doses of an active composition into a laundry washing machine, a dryer or a dishwashing machine, which enables more than one dose to be dispensed (in either one or more washing, drying or dishwashing rinse cycles) and is triggered independently of the commands of an operating program in the machine or intervention by the user.
This objective is achieved by the invention using an apparatus of the generic type having a supply chamber for containing at least double the quantity of an individual dose of the active composition. Connected to the supply chamber by a passage is a dispensing chamber for containing a single dose of the active composition and releasing the same via a discharge passage into the interior of the machine. Means are provided for opening the discharge passage and closing, beforehand or simultaneously, the passage between the supply chamber and dispensing chamber. The opening means are operated by means that are activated by conditions prevailing in the interior of the machine, which occur exclusively during a washing, drying or dishwashing cycle. Means are also provided for re-opening the passage between the supply chamber and the dispensing chamber and closing, beforehand or simultaneously, the discharge passage of the dispensing chamber in order to refill the same from the supply chamber.
In a first embodiment the apparatus proposed by the invention comprises a fluid reservoir; an expansion mechanism and a one-way valve disposed between the fluid reservoir and the expansion mechanism, so that fluid is able to flow between the fluid reservoir and the expansion mechanism. An opening/closing mechanism is operated by the expansion mechanism, in such a way that the discharge passage of the dispensing chamber is opened and the passage between the supply chamber and the dispensing chamber is closed, beforehand or simultaneously, to enable the contents of the dispensing chamber to be substantially entirely released into the machine. A return mechanism re-positions the opening/closing mechanism in the initial position; and means are provided to enable the hydraulic fluid to leave the expansion mechanism when the opening/closing mechanism is re-set by the return mechanism.
Accordingly, the flow of fluid from the fluid reservoir into the expansion mechanism is operated either by the wet laundry or dry laundry compressing the fluid reservoir directly or indirectly, in which case the opening/closing mechanism is preferably a gate valve, or by a pivotably mounted weight exerting pressure on the fluid reservoir due to the rotation of the apparatus with the washing machine or dryer drum, in which case the opening/closing mechanism is preferably a float valve. In both cases the return mechanism is preferably a return spring.
In another embodiment, the apparatus proposed by the invention comprises a one-way valve between the supply chamber and the dispensing chamber. A water chamber with a one-way valve is provided so that, at the start of an operating cycle, water disposed in the machine flows through the one-way valve into the water chamber, expanding it to the degree that the dispensing chamber is compressed. A discharge passage of the dispensing chamber is opened and, beforehand or simultaneously, the one-way valve between supply chamber and dispensing chamber is closed to permit the contents of the dispensing chamber to be substantially entirely released into the machine. Means are provided to enable the water slowly to leave the water chamber, causing the dispensing chamber to expand again. As a result, the one-way valve between the supply chamber and the dispensing chamber is opened and, beforehand or simultaneously, the discharge passage of the dispensing chamber is closed to allow the dispensing chamber to be filled from the supply chamber again. The means enabling the water to leave the water chamber preferably comprises small orifices.
In a further embodiment the apparatus proposed by the invention comprises a one-way valve between the supply chamber and the dispensing chamber. Means which alter in form, at least to a certain degree, when the temperature is increased, cause the dispensing chamber to be compressed, the discharge passage of the dispensing chamber to be opened and, beforehand or simultaneously, the one-way valve between supply chamber and dispensing chamber to be closed, to enable the contents of the dispensing chamber to be substantially entirely released into the machine. The means which alter in form undergo a reverse change of form, at least to a certain degree, on cooling, causing the one-way valve between the supply chamber and the dispensing chamber to be opened again and, beforehand or simultaneously, the discharge passage of the dispensing chamber to be closed, in order to refill the dispensing chamber from the supply chamber.
An alternative to this further embodiment of the invention is characterized by a rigid chamber with a material disposed therein, in particular a wax, which expands as the temperature increases and shrinks on cooling. Preferably, the supply chamber is designed so that it contains a wax. This being the case, it is preferable if the opening mechanism is raised by means of a flexible diaphragm, which responds to the expansion of the material.
The apparatus proposed by the invention is additionally characterized by a bimetallic strip, which bends when the temperature increases and returns to shape on cooling.
Particularly preferred, the supply chamber is designed so that it can be re-filled from the exterior.
In one particularly practical arrangement, the apparatus proposed by the invention is firmly but detachably secured in the interior of the machine.